Evolve Long Tube Manifolds - BMW E60/E61 M5 | E63/E64 M6

Designed for maximum performance the Evolve tubular headers deliver a substantial power increase over the stock headers. The power is achieved by a combination of eliminating the highly restrictive primary catalytic converters and it's long tube larger diameter pipe work. Performance gains of between 35-50hp and 40-50 lb.ft torque.  Features: Constructed from 304 grade stainless steel 5-1 Step Design Header F1 Style TIG Welded Flow Optimised Slip-on Merge Collector TIG Welded The radical design requires major changes to the ignition, fuel and VANOS maps to achieve best performance through the RPM range.  The stock DME calibration is suited to the high back pressure smaller diamater stock header system.  Once the flow characteristics of are changed by a radical design such as this it becomes essential to recalibrate the DME.